Steam gasification of poultry litter biochar for bio-syngas production

Abstract

Poultry litter, the major waste generated by poultry farming, has its main use in soil as a fertilizer. However, the uncontrolled use of poultry litter for this purpose can result in environmental impacts such as the emission of methane, a greenhouse gas. Therefore, the thermochemical conversion of this waste can be a solution to this problem, since its products can be converted into useful energy. In this work, pyrolysis experiments were conducted in a tubular reactor, using N₂ atmosphere and a final temperature of 800 °C. Furthermore, the steam gasification of poultry litter biochar obtained in the pyrolysis experiments was investigated in a fixed-bed tubular reactor at different temperatures (800, 850 and 900 °C). The maximum hydrogen (H₂) reaction rates were observed in the first 15 min of the reaction, and there was a change in the maximum reaction rate towards lower reaction times with increased temperature. The elevated H₂ yield may be associated with metals present in the biochar, especially potassium (K). Bio-syngas (H₂ + CO) obtained from steam gasification of poultry litter biochar presented high potential to reduce iron ore by indirect reduction (IR) in blast furnaces (BF), or in direct reduced iron (DRI) processes.